package bot import ( "reflect" "strings" "github.com/diamondburned/arikawa/api" "github.com/diamondburned/arikawa/discord" "github.com/diamondburned/arikawa/gateway" "github.com/pkg/errors" ) // Break is a non-fatal error that could be returned from middlewares to stop // the chain of execution. var Break = errors.New("break middleware chain, non-fatal") // filterEventType filters all commands and subcommands into a 2D slice, // structured so that a Break would only exit out the nested slice. func (ctx *Context) filterEventType(evT reflect.Type) (callers [][]caller) { // Find the main context first. callers = append(callers, ctx.eventCallers(evT)) for _, sub := range ctx.subcommands { // Find subcommands second. callers = append(callers, sub.eventCallers(evT)) } return } func (ctx *Context) callCmd(ev interface{}) (bottomError error) { evV := reflect.ValueOf(ev) evT := evV.Type() var callers [][]caller // Hit the cache t, ok := ctx.typeCache.Load(evT) if ok { callers = t.([][]caller) } else { callers = ctx.filterEventType(evT) ctx.typeCache.Store(evT, callers) } for _, subcallers := range callers { for _, c := range subcallers { _, err := c.call(evV) if err != nil { // Only count as an error if it's not Break. if err = errNoBreak(err); err != nil { bottomError = err } // Break the caller loop only for this subcommand. break } } } var msc *gateway.MessageCreateEvent // We call the messages later, since we want MessageCreate middlewares to // run as well. switch { case evT == typeMessageCreate: msc = ev.(*gateway.MessageCreateEvent) case evT == typeMessageUpdate && ctx.EditableCommands: up := ev.(*gateway.MessageUpdateEvent) // Message updates could have empty contents when only their embeds are // filled. We don't need that here. if up.Content == "" { return nil } // Query the updated message. m, err := ctx.Store.Message(up.ChannelID, up.ID) if err != nil { // It's probably safe to ignore this. return nil } // Treat the message update as a message create event to avoid breaking // changes. msc = &gateway.MessageCreateEvent{Message: *m, Member: up.Member} // Fill up member, if available. if m.GuildID.Valid() && up.Member == nil { if mem, err := ctx.Store.Member(m.GuildID, m.Author.ID); err == nil { msc.Member = mem } } // Update the reflect value as well. evV = reflect.ValueOf(msc) default: // Unknown event, return. return nil } // There's no need for an errNoBreak here, as the method already checked // for that. return ctx.callMessageCreate(msc, evV) } func (ctx *Context) callMessageCreate(mc *gateway.MessageCreateEvent, value reflect.Value) error { // check if bot if !ctx.AllowBot && mc.Author.Bot { return nil } // check if prefix pf, ok := ctx.HasPrefix(mc) if !ok { return nil } // trim the prefix before splitting, this way multi-words prefices work content := mc.Content[len(pf):] if content == "" { return nil // just the prefix only } // parse arguments parts, err := ctx.ParseArgs(content) if err != nil { return errors.Wrap(err, "failed to parse command") } if len(parts) == 0 { return nil // ??? } // Find the command and subcommand. arguments, cmd, sub, err := ctx.findCommand(parts) if err != nil { return errNoBreak(err) } // We don't run the subcommand's middlewares here, as the callCmd function // already handles that. // Run command middlewares. if err := cmd.walkMiddlewares(value); err != nil { return errNoBreak(err) } // Start converting var argv []reflect.Value var argc int // the last argument in the list, not used until set var last Argument // Here's an edge case: when the handler takes no arguments, we allow that // anyway, as they might've used the raw content. if len(cmd.Arguments) == 0 { goto Call } // Argument count check. if argdelta := len(arguments) - len(cmd.Arguments); argdelta != 0 { var err error // no err if nil // If the function is variadic, then we can allow the last argument to // be empty. if cmd.Variadic { argdelta++ } switch { // If there aren't enough arguments given. case argdelta < 0: err = ErrNotEnoughArgs // If there are too many arguments, then check if the command supports // variadic arguments. We already did a length check above. case argdelta > 0 && !cmd.Variadic: // If it's not variadic, then we can't accept it. err = ErrTooManyArgs } if err != nil { return &ErrInvalidUsage{ Prefix: pf, Args: parts, Index: len(parts) - 1, Wrap: err, Ctx: cmd, } } } // The last argument in the arguments slice. last = cmd.Arguments[len(cmd.Arguments)-1] // Allocate a new slice the length of function arguments. argc = len(cmd.Arguments) - 1 // arg len without last argv = make([]reflect.Value, 0, argc) // could be 0 // Parse all arguments except for the last one. for i := 0; i < argc; i++ { v, err := cmd.Arguments[i].fn(arguments[0]) if err != nil { return &ErrInvalidUsage{ Prefix: pf, Args: parts, Index: len(parts) - len(arguments) + i, Wrap: err, Ctx: cmd, } } // Pop arguments. arguments = arguments[1:] argv = append(argv, v) } // Is this last argument actually a variadic slice? If yes, then it // should still have fn normally. if last.fn != nil { // Allocate a new slice to append into. vars := make([]reflect.Value, 0, len(arguments)) // Parse the rest with variadic arguments. Go's reflect states that // varidic parameters will automatically be copied, which is good. for i := 0; len(arguments) > 0; i++ { v, err := last.fn(arguments[0]) if err != nil { return &ErrInvalidUsage{ Prefix: pf, Args: parts, Index: len(parts) - len(arguments) + i, Wrap: err, Ctx: cmd, } } arguments = arguments[1:] vars = append(vars, v) } argv = append(argv, vars...) } else { // Create a zero value instance of this: v := reflect.New(last.rtype) var err error // return error switch { // If the argument wants all arguments: case last.manual != nil: // Call the manual parse method: _, err = callWith(last.manual.Func, v, reflect.ValueOf(arguments)) // If the argument wants all arguments in string: case last.custom != nil: // Manual string seeking is a must here. This is because the string // could contain multiple whitespaces, and the parser would not // count them. var seekTo = cmd.Command // We can't rely on the plumbing behavior. if sub.plumbed != nil { seekTo = sub.Command } // Seek to the string. if i := strings.Index(content, seekTo); i > -1 { // Seek past the substring. i += len(seekTo) content = strings.TrimSpace(content[i:]) } // Call the method with the raw unparsed command: _, err = callWith(last.custom.Func, v, reflect.ValueOf(content)) } // Check the returned error: if err != nil { return err } // Check if the argument wants a non-pointer: if last.pointer { v = v.Elem() } // Add the argument into argv. argv = append(argv, v) } Call: // call the function and parse the error return value v, err := cmd.call(value, argv...) if err != nil { return err } switch v := v.(type) { case string: v = sub.SanitizeMessage(v) _, err = ctx.SendMessage(mc.ChannelID, v, nil) case *discord.Embed: _, err = ctx.SendMessage(mc.ChannelID, "", v) case *api.SendMessageData: if v.Content != "" { v.Content = sub.SanitizeMessage(v.Content) } _, err = ctx.SendMessageComplex(mc.ChannelID, *v) } return err } // findCommand filters. func (ctx *Context) findCommand(parts []string) ([]string, *MethodContext, *Subcommand, error) { // Main command entrypoint cannot have plumb. for _, c := range ctx.Commands { if c.Command == parts[0] { return parts[1:], c, ctx.Subcommand, nil } // Check for alias for _, alias := range c.Aliases { if alias == parts[0] { return parts[1:], c, ctx.Subcommand, nil } } } // Can't find the command, look for subcommands if len(args) has a 2nd // entry. for _, s := range ctx.subcommands { if s.Command != parts[0] { continue } // Only actually plumb if we actually have a plumbed handler AND // 1. We only have one command handler OR // 2. We only have the subcommand name but no command. if s.plumbed != nil && (len(s.Commands) == 1 || len(parts) <= 2) { return parts[1:], s.plumbed, s, nil } if len(parts) >= 2 { for _, c := range s.Commands { if c.Command == parts[1] { return parts[2:], c, s, nil } // Check for aliases for _, alias := range c.Aliases { if alias == parts[1] { return parts[2:], c, s, nil } } } } // If unknown command is disabled or the subcommand is hidden: if ctx.SilentUnknown.Subcommand || s.Hidden { return nil, nil, nil, Break } return nil, nil, nil, &ErrUnknownCommand{ Parts: parts, Subcmd: s, } } if ctx.SilentUnknown.Command { return nil, nil, nil, Break } return nil, nil, nil, &ErrUnknownCommand{ Parts: parts, Subcmd: ctx.Subcommand, } } func errNoBreak(err error) error { if errors.Is(err, Break) { return nil } return err }